Checking any of this yourself

None of it asks to be taken on trust. Open your browser's developer tools, switch to the Network panel and reload a tool page. You will see the page's own files, the font request described above, and an advertising request if advertising is running. That is the whole list.

Use a tool with that panel open and watch it stay empty. Then open the Application (or Storage) tab and look for bench-theme: that one entry is the whole of what this site keeps in your browser.

If the Network panel ever shows a request this page does not describe, that is a fault in the policy as much as in the page. Write to moanacrab7610@gmail.com and say what you saw.